Aerosol valve actuator

Abstract

An aerosol valve actuator internally forms a cylinder containing a rigid bodily slidable reciprocating piston behind the actuator's orifice and from which a piston rod extends forwardly with a forward end forming a valve head normally seating on the inside surface of the actuator surrounding its orifice, a spring biasing the piston and piston rod forwardly to normally seal the orifice closed. The actuator has a hole receiving the aerosol valve stem and mounting the actuator on this stem, this hole opening transversely inside of the actuator between the front of the piston and the orifice. When the actuator is finger-pressed to depress the aerosol valve stem and open the valve to release a pressurized product from an aerosol package container having the valve, the product enters the actuator, forcing the piston and piston rod backwardly to a retracted piston against the bias of the spring, so that the product discharges through the actuator's orifice, finger release causing the aerosol valve to close, and the pressure within the actuator to drop, resulting in the spring pushing the piston and piston rod forwardly to seal the actuator's orifice closed. The piston and piston rod form a piston area which relative to the flow rate capacity of the actuator's orifice, and the position the actuator's valve stem hole opens into the actuator between its piston and orifice, causes the piston to remain steadily at its retracted position during the discharge of the product. The back end of the actuator has a governor for determining the rate of discharge effected by the actuator through its orifice, this governor being a cap screwed on the back end of the actuator and having an abutment surface against which the piston abuts when forced backwardly by the pressure of the product, thus establishing the retracted position of the piston and piston rod and, therefore, the rate of discharge via the actuator's orifice. This governor can be screwed forwardly to keep the actuator'orifice sealed even when the actuator is depressed to open the aerosol valve, and by screwing the governor backwardly, discharge via the actuator becomes possible but at a rate governed by the amount the governor is screwed backwardly.

Description

BACKGROUND OF THE INVENTION

This invention relates to the actuators or buttons applied to the aerosol valve stems of aerosol packages in particular.

The science and technology of such packages and their components are described by the text "Aerosols: Science and Technology", published by Interscience Publishers, Inc., New York, copyrighted 1961, the entire contents of this text being hereby incorporated by this reference into the present application.

The prior art has recognized that such actuators involve the problem of clogging and has made various attempts at solving this problem as exemplified by the following patents:

McKernan U.S. Pat. No. 3,250,474, dated May 10, 1966

Barker U.S. Pat. No. 3,378,205, dated Apr. 16, 1968

Venus, Jr. U.S. Pat. No. 3,427,270, dated Apr. 8, 1969

Lewiecki et al. U.S. Pat. No. 3,428,223, dated Feb. 18, 1969

Beard U.S. Pat. No. 3,545,682, dated Dec. 8, 1970

Grothoff U.S. Pat. No. 3,602,407, dated Aug. 31, 1971

None of the constructions of the above patents have ever been applied to commercial aerosol packages, insofar as is known. They all have inherent disadvantages.

One disadvantage is that when any such actuator receives the pressurized product from the aerosol valve stem of an aerosol package, unsealing its orifice, the pressure drop occurring within the actuator adjacent to the actuator's orifice, causes the orifice to become resealed, this action occurring repeatedly with great rapidity to produce a chattering action. This follows from the fact that all anti-clogging or self-sealing actuators rely on the pressure of the product for unsealing, this pressure acting against a piston area provided in one way or another, and against some form of elastic means normally biasing the valve arrangement involved to a normally closed position sealing the actuator's orifice so that product trapped within the actuator is sealed against the atmosphere which might otherwise solidify the product within the actuator.

Such actuators are necessarily very small in dimensions and another diaadvantage has been that the prior art actuators have involved parts which cannot be easily injection molded as rigid plastic parts capable of assembly by mass production methods, keeping in mind the very large quantities of aerosol packages involved by the production of any one kind of package.

Even conventional actuators which do involve the clogging problem and which are of one-piece construction and capable of being injection molded in the large quantities required, have the disadvantage, shared by the non-clogging actuator proposals, that the discharge rate is unvariably fixed by the discharge orifice diameter. In many instances, it would be desirable to be able to vary the discharge rate of an aerosol package under control by the user of the package.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a non-clogging aerosol valve stem actuator, sometimes called a button, which is free from the disadvantages described above.

The actuator of the present invention is particularly intended to be one for the valve stem of an aerosol valve forming part of an aerosol package containing a fluid product, which may be of varying viscosity and composition, and which is pressurized by a propellant either directly by the product being a mixture or solution including any of the usual pressurized gas propellants, or indirectly, as in the case of packages using the "Power Flo" or "Sepro" types of containers, respectively made substantially as shown by the Bruce et al. U.S. Pat. No. 3,392,842, July 23, 1968 and the Krizka U.S. Pat. No. 3,433,391, Mar. 18, 1969. However, the actuator may be used either as an actuator or as an attachment in the case of packages ejecting a pressurized fluid product, in the sense that the product is under pressure, via actuation of a finger or hand-operated mechanical pump.

According to the invention, the actuator is made of substantially rigid parts and particularly parts made of plastic capable of being injection molded via an injection molding machine. Any of the plastics currently used for making the conventional one-piece actuator or button are suitable such as are soft enough to make press-fits over the aerosol valve stem, yet rigid enough to operate under the forces involved without appreciable bending. Examples are polyethylene, nylon, polypropylene and the like.

In the above sense, the actuator body is substantially rigid and it has a front end in which a dispensing orifice is formed, and a closed back end, the body forming a passage extending between these ends, at least a portion of this passage adjacent to the back end of the body forming a cylinder. In the same sense, a substantially rigid piston is reciprocatively positioned in this cylinder and is made preferably integrally with a piston rod extending forwardly and which has a forward sealing end which closes the orifice by seating on the inside of the body's front end, when the piston is at an advanced position. Reciprocation of the piston to a retracted position opens the orifice, and the body contains means for elastically biasing the piston and piston rod towards an advanced or forward position so that the sealing end of the piston rod normally closes the orifice, this biasing means being exemplified by a compression coil spring connecting the piston and piston rod with the back end of the actuator body, providing the reaction for the spring. The body is formed with a hole for receiving the tubular aerosol valve stem and attachment to the latter via the usual press fit, and this hole opens into the described passage between the piston and the front end of the piston rod.

Depression of the aerosol valve stem via the actuator, as by finger pressure, causes the pressurized product to discharge via the hole into the passage within the actuator body and via this product applying its pressure to the piston and forcing the piston to its retracted position, the product being then allowed to flow through the passage and out through the dispensing orifice in the front end of the actuator.

The back end of the cylinder in the actuator body, is closed by the back end surface of the body surrounding the back end of the cylinder, being externally threaded and a cap having a side wall with an internal screw thread which is screwed on this back end. This cap has an internal abutment surface engaged by the piston when in its retracted position and because the cap can be screwed in and out, the retracted position of the piston can be adjusted as to its location and therefore, the distance the front sealing end of the piston rod can separate from its sealing position with respect to the actuator's discharge or dispensing orifice. In other words, the cap provides a governor for the actuator which governs the discharge rate possible when the aerosol valve is opened by depression of its valve stem via the actuator.

The piston and piston rod are prevented from rotating when the cap or governor is rotated, via a connection with the inside of the actuator body permitting the reciprocation of the piston and piston rod, but locking them against rotation.

Complete unscrewing of the cap or governor is prevented by one of the parts having a nib or lug and other a detent or some similar arrangement, which cooperate to prevent inadvertent removal of the cap when it is unscrewed to provide the maximum discharge rate of which the actuator is capable via its discharge orifice, which is of course, of fixed diameter. This locking arrangement is preferably made so that its resistance can be forcibly overcome by forcible unscrewing, permitting removal of the cap or governor and of the spring and piston and piston rod. This may be desirable as an emergency expedient in the very unlikely event the actuator becomes clogged in spite of the fact that after each actuation, its discharge orifice is sealed fluid and air tight, separating any product trapped within the actuator from the outside atmosphere.

All of the parts of the actuator may be injection molded from suitable plastic with the exception of the spring which may be made of coiled spring wire. Assembly is easy because the piston and piston rod need only to be slipped within the actuator body with the spring in place and the cap governor then screwed on.

Working prototypes of this new actuator have proven to be non-chattering. The valve stem hole opens into the passage somewhat closer to the forward face of the piston than it does to the front end of the actuator having the discharge orifice and the sealing front end of the piston rod, and it is believed that this is one reason that chattering is avoided. Also, the inherent design of this new actuator permits the piston and piston rod to be designed to present a piston area facing the front end of the actuator and which receives the pressurized product, and a discharge orifice flow rate capacity, at the pressure and consistency of the product being dispensed, which are relatively proportioned to maintain the pressure applied to the piston during operation of the actuator, at a value holding the piston at its retracted position continuously as long as the product flows through the passage and out through the discharge or dispensing orifice of the actuator.

The cap or governor has the additional advantage that it can be screwed inwardly far enough to lock the piston and piston rod in their advanced position and completely sealing the dispensing or discharge orifice of the actuator, closed against inadvertent discharge. This has the advantage that the various available child-proof arrangements intended to prevent unscrewing of caps in general by children, can be applied to the flow cap or governor of this actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

The presently preferred mode for carrying out this invention is schematically illustrated by the accompanying drawings in which:

FIG. 1 illustrates in perspective an aerosol product package to which the actuator is applied;

FIG. 2 is a vertical section through FIG. 1 showing that in this instance the package is of the "Power Flo" container type;

FIG. 3 is a vertical section through the actuator showing it when locked closed to prevent the discharge of the packaged product;

FIG. 4 is the same as FIG. 3 but shows the governor cap unscrewed far enough to put the actuator into its operative condition;

FIG. 5, again the same as FIG. 3, but with considerable exaggeration for illustrative purposes, shows the actuator parts during the dispensing or discharging of the packaged pressurized product;

FIG. 6 is a cross section taken on the line 6--6 in FIG. 3;

FIG. 7 is a cross section taken on the line 7--7 in FIG. 5;

FIG. 8 is a perspective view showing the external appearance of the actuator prior to its application to the aerosol valve stem; and

FIG. 9 is an exploded view showing the manner in which the actuator parts can be assembled.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated, the aerosol package of FIGS. 1 and 2 comprises the usual can body 1 having what may be a conventional aerosol valve 2 and, in this case, the easy deformable flexible bag 3 which contains the product 4, the product being pressurized by vapor between the bag 3 and the can 1 generated by a small pool of propellant 5 shown in the bottom of the can. In other types of packages the propellant and the product may be mixed or dissolved together. In the pump type of package, the fluid product is pressurized because under the pressure applied via the pump.

In the present instance, the aerosol valve has the tubular valve stem 6 through which the pressurized product discharges when the stem is depressed to open the aerosol valve 2. Technically, the stem is part of the aerosol valve.

It is to this stem that the actuator or button 7 is press-fitted so that it may conveniently receive finger pressure to open the aerosol valve with the product being dispensed or discharged horizontally as indicated by the arrow 8 in FIG. 2.

Referring now to FIGS. 3 through 5, the valve 7 is shown as comprising the substantially rigid plastic body 9 having the hole 10 formed upwardly therein for receiving the valve stem 6 via the usual press fit. The body 9 has a horizontal passage 11 formed through it transversely with respect to the axis of the hole 10 and into which this hole 10 opens as at 10a. The body has a front end wall 12 closing the adjacent or front end of the passage 11 and it is in this front end wall that the discharge orifice 13 is formed. The diameter of this orifice may be in the area of from about 0.002 to about 0.050 inches, but its exact diameter depends on the type of formulation dispensed and the delivery effect desired.

At least the back or left-hand end portion of the passage 11 is formed as a cylinder 14 and the cylinder contains a substantially rigid plastic reciprocating piston 15 which slides bodily within the cylinder. This piston, preferably integrally, has a piston rod or elongated portion 16 extending forwardly or to the right in the drawings, with a front end 17 engaging the inside of the front end wall 12 via its surface around the orifice 13. This forward piston rod end 17 is designed to seal the orifice 13 fluid-tightly and air-tightly closed when the piston and its rod are at an advanced position as shown in FIGS. 3 and 4, and separating from the front end wall when the piston and its rod are at the retracted position, as shown on a very exaggerated scale in FIG. 5. Actually, the piston and piston rod movement between retracted and forward positions is very small. For normal operation of the actuator, the maximum distance of separation required is that which permits the product to flow through the orifice at the maximum flow rate that the size of the orifice permits.

The body has an external cylindrical back end surface 18 surrounding the back end of the cylinder 14, and which is externally screw-threaded as shown at 19. The product discharge governor previously referred to, is formed by a cap 20 having a skirt with internal screw threads 21, the cap 20 being screwed onto the threaded surface of the cylindrical backward projection or part of the actuator body. This cap provides the internal abutment surface 22 which limits the backward motion or retraction of the piston and piston rod. In this way the exact location of the retracted piston position can be governed or controlled. When the governor cap 20 is screwed fully inwardly as shown in FIG. 3, the front end 17 of the piston rod 16 is pressed tightly against the inside surface of the front end wall 12, sealing the orifice 13 closed whether or not the aerosol valve itself is opened by depression of its valve stem via the actuator. Although not shown, the cap governor is adaptable to the usual child-proof arrangements now used for screw caps in general.

When the governor cap is unscrewed varying extends, the piston and piston rod can move backwardly or retract varying distances, the exact retracted position being fixed by the position of the abutment 22 effected by the adjustment of the governor cap 20. When the actuator is depressed to open the aerosol valve, the pressurized fluid flows into the actuator as shown by FIG. 5, its pressure against the forward end of the piston 15 forcing the latter back and against the abutment 22 with the piston rod 16 moving with the piston, the front end 17 unsealing the discharge or dispensing orifice 13 so that the pressurized fluid is ejected via the orifice 13. Although not shown, it is to be understood that the end 17 of the piston rod and the interior surface of the front end wall 12 around the orifice 13 maybe respectively contoured in any of the usual ways intended to effect sealing with the maximum effectiveness.

A metal compression coil spring 23 is positioned between the inside of the cap governor 20 and the back end of the piston 15 and its piston rod 16 to bias the piston 15 and its rod to their forward position. The pressure of the discharging fluid product is shown in FIG. 5 as compressing this spring 23. A vent hole 20a is formed in the cap so air is not trapped behind the piston.

Guide vanes 24 are shown as radiating from the piston rod 16, these fitting in guideways 25 formed by the body in its passage 11, this arrangement locking the piston and piston rod against rotation while permitting the longitudinal reciprocating action required for operation of the actuator.

To prevent inadvertent complete unscrewing of the governor cap, the cap is shown with a lug 26 on its threads which engages a detent 27 formed on the threaded cylinder part or back end 18 of the actuator body. The parts are made of plastics which although rigid, are elastically deformable to some extent, so forcible unscrewing of the governor cap 20 causes disengagement of these retaining members so that the valve can be disassembled by the user as shown by FIG. 9, in the unlikely event clogging should occur.

The above lug and detent are positioned to engage just safely before the can can be completely unscrewed. For childproofing, a detent 27a engaged by the lug can be positioned to interengage when the cap governor is screwed into its forwardmost position sealing the orifice closed. The force required for disengagement of the lug 26 from this detent 27a can be made so that only an adult can unscrew the cap governor to make the actuator operative.

The piston and cap may be interconnected so they can be withdrawn as one, FIG. 9 actually showing the assembly of the actuator. In this instance, the piston is formed with a chamber 28 having a hole facing the abutment member 22 and the latter has a projection with a tapered end 29 which during assembly of the valve, can be forced through the hole into the chamber 28, effecting an interlocking. Complete unscrewing of the cap leaves the spring 23 and the piston and piston rod as interconnected parts.

Although not shown, connection of the spring 23 to the piston and piston rod would also be effective, without the parts being interlocked, unscrewing of the governor cap 20 permitting the spring to eject so that via the spring, the piston and piston can be picked out manually from the actuator body.

With many products a swirl chamber is desired or required for producing a swirling action as the product discharges through the orifice. The present invention easily permits such an arrangement, the inside of the front end wall 12 being shown as having backwardly projecting vanes or baffles 30, forming male elements, which in cross section have the contour of spiral or arcuate or curved segments with ends which either overlap or are adjacent to each other, the front end of the piston rod 16 having recesses 31 or female elements of corresponding shape in which the baffles 30 fit with a sliding fit but which is made to be substantially fluid-tight. In the discharging condition as shown by FIG. 5, and having reference to FIG. 7, the discharging product flows through the ends of these baffles and receives a swirling motion prior to ejection through the discharge or dispensing orifice of the actuator. The swirl chamber parts are held properly oriented because the piston and its rod are non-rotative as previously described.

As previously noted, prototypes of this non-clogging actuator have not been subject to chattering. It is believed that one reason is that the hole opening 10a is positioned more closely to the inside of the piston 15 than it is to the discharge orifice 13. Another reason is believed to be that due to the inherent design of the actuator, the piston are presented by the front end of the piston 15 and the front end 17 of its piston rod, can be made very large relative to the required diameter of the discharge orifice 13. For example, with the actuator having external dimensions appropriate for an aerosol valve actuator, the piston may have a diameter of 0.398 inches with the forward end of the piston rod having an overall diameter of 0.205 inches, whereas the orifice diameter that is appropriate may be in the usual range previously indicated. These factors may account for the actuator having the capability of producing a steady discharge upon opening of the aerosol valve.

It is to be understood that with changes in the rate the product is discharged, there will ordinarily be changes in the spray pattern obtained. Thus, with the governor adjusted so that the orifice is unsealed only slightly, a widely dispersed spray may be obtained with a maximum of mechanical break-up of the product; with the governor adjusted for a maximum discharge, the minimum of mechanical break-up may be obtained.

Claims

What is claimed is:

1. An actuator for dispensing a pressurized product and comprising a hollow body having an interior and provided with means for receiving the pressurized product in said interior, said body having a front end wall open to said interior and through which a product-discharge orifice is formed, said body containing a valve having a front end normally seating on the inside of said end wall and closing said orifice and means responsive to fluid pressure of said product in said interior for unseating the valve's front end while said pressure exists and for reseating the valve's front end when said pressure is substantially reduced, and limit means for controlling the extent said valve can unseat, the valve's front end and the inside of said front end wall respectively having cooperative, relatively reciprocative male and female parts with one part fixed to the valve's front end and the other part fixed to the body's front wall inside, a first of said parts in cross section forming baffle means substantially surrounding said orifice and having circumferential ends which are interspaced to form at least one space through which the pressurized product can flow transversely with respect to said orifice, a second of said parts normally closing said space and slidingly fitting in said first part, unseating of said valve to the extent controlled by said limit means separating said parts axially so pressurized product in said interior can flow through the space between said interspaced ends to the extent said parts are slid apart by unseating of said valve.

2. The actuator of claim 1 in which the first of said parts is fixed to the inside of the body's said front end wall and said baffle means is formed by curved baffles having their respepctive ends interspaced from each other, and said second of said parts is formed by recesses in the valve's said front end and which slidingly fit and receive the radially inner and outer sides of said baffles, unseating of the valve withdrawing its front end having said recesses, from the baffle means and said circumferentially interspaced ends.

3. The actuator of claim 1 in which said limit means is for adjustably limiting the extent said valve can unseat.

4. An aerosol valve stem actuator comprising a substantially rigid plastic body having a hole formed upwardly therein for receiving said stem and a passage formed therethrough transversely with respect to said hole and into which said hole opens, said body forming a front end wall closing the adjacent end of said passage, said front end wall having a discharge orifice formed therethrough, said passage having at least a back end portion forming a cylinder, said passage containing a substantially rigid slidable plastic reciprocating piston positioned in said cylinder and having a piston rod extending forwardly with a front end engaging said front end wall around said orifice and closing said orifice when said piston is at an advanced position and separating from said front end wall when said piston is at a retracted position, said body having an external back end surface surrounding the back end of said cylinder, said surface having screw threads, a product discharge governor formed by a cap having a side wall with internal screw threads and screwed on the screw threads of said surface, said cap having an internal abutment surface engaged by said piston when in its retracted position and adjustably fixing said position dependent on the position of said cap, and a coil compression spring connected with the inside of said cap and extending forwardly and connected to said piston to bias the piston to its said advanced position with its said piston rod front end engaging said front end wall around said orifice and normally closing said orifice.

5. The actuator of claim 4 in which said piston and piston rod form a piston area facing said front end, and said discharge orifice has a flow rate capacity at the pressure and constituancy of said product, said area and said rate being relatively proportioned to maintain said pressure applied to said piston at a value holding said piston at its said retracted position continuously as long as said product flows through said passage and through said dispensing orifice.

6. The actuator of claim 4 in which said hole opens transversely into said passage at a location spaced far enough backwardly from said orifice and towards said piston for the latter to be continuously forced to its said retracted position constantly during maintenance of said flow.

7. The actuator of claim 4 in which said front end of said piston rod and the inside of said front end body wall respectively have female and male slidingly interfitting elements contoured substantially as curved segments to form a swirl chamber.

8. The actuator of claim 7 in which said piston rod and the inside of said surface have slidably interfitting guide elements holding said piston rod and piston against rotation.

9. The actuator of claim 1 in which said governor cap can be removed from said body by unscrewing and said piston and piston rod are removable from said actuator body when said governor cap is removed from said body.

10. The actuator of claim 9 having means for resisting unscrewing of said governor cap from said actuator body but which may be overridden by forcible unscrewing of said cap.